[linux-2.6-block.git] / crypto / michael_mic.c

/*
 * Cryptographic API
 *
 * Michael MIC (IEEE 802.11i/TKIP) keyed digest
 *
 * Copyright (c) 2004 Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <asm/byteorder.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <linux/types.h>


struct michael_mic_ctx {
	u8 pending[4];
	size_t pending_len;

	u32 l, r;
};


static inline u32 xswap(u32 val)
{
	return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
}


#define michael_block(l, r)	\
do {				\
	r ^= rol32(l, 17);	\
	l += r;			\
	r ^= xswap(l);		\
	l += r;			\
	r ^= rol32(l, 3);	\
	l += r;			\
	r ^= ror32(l, 2);	\
	l += r;			\
} while (0)


static void michael_init(struct crypto_tfm *tfm)
{
	struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
	mctx->pending_len = 0;
}


static void michael_update(struct crypto_tfm *tfm, const u8 *data,
			   unsigned int len)
{
	struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
	const __le32 *src;

	if (mctx->pending_len) {
		int flen = 4 - mctx->pending_len;
		if (flen > len)
			flen = len;
		memcpy(&mctx->pending[mctx->pending_len], data, flen);
		mctx->pending_len += flen;
		data += flen;
		len -= flen;

		if (mctx->pending_len < 4)
			return;

		src = (const __le32 *)mctx->pending;
		mctx->l ^= le32_to_cpup(src);
		michael_block(mctx->l, mctx->r);
		mctx->pending_len = 0;
	}

	src = (const __le32 *)data;

	while (len >= 4) {
		mctx->l ^= le32_to_cpup(src++);
		michael_block(mctx->l, mctx->r);
		len -= 4;
	}

	if (len > 0) {
		mctx->pending_len = len;
		memcpy(mctx->pending, src, len);
	}
}


static void michael_final(struct crypto_tfm *tfm, u8 *out)
{
	struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
	u8 *data = mctx->pending;
	__le32 *dst = (__le32 *)out;

	/* Last block and padding (0x5a, 4..7 x 0) */
	switch (mctx->pending_len) {
	case 0:
		mctx->l ^= 0x5a;
		break;
	case 1:
		mctx->l ^= data[0] | 0x5a00;
		break;
	case 2:
		mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;
		break;
	case 3:
		mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
			0x5a000000;
		break;
	}
	michael_block(mctx->l, mctx->r);
	/* l ^= 0; */
	michael_block(mctx->l, mctx->r);

	dst[0] = cpu_to_le32(mctx->l);
	dst[1] = cpu_to_le32(mctx->r);
}


static int michael_setkey(struct crypto_tfm *tfm, const u8 *key,
			  unsigned int keylen)
{
	struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
	const __le32 *data = (const __le32 *)key;

	if (keylen != 8) {
		tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
		return -EINVAL;
	}

	mctx->l = le32_to_cpu(data[0]);
	mctx->r = le32_to_cpu(data[1]);
	return 0;
}


static struct crypto_alg michael_mic_alg = {
	.cra_name	= "michael_mic",
	.cra_flags	= CRYPTO_ALG_TYPE_DIGEST,
	.cra_blocksize	= 8,
	.cra_ctxsize	= sizeof(struct michael_mic_ctx),
	.cra_module	= THIS_MODULE,
	.cra_alignmask	= 3,
	.cra_list	= LIST_HEAD_INIT(michael_mic_alg.cra_list),
	.cra_u		= { .digest = {
	.dia_digestsize	= 8,
	.dia_init	= michael_init,
	.dia_update	= michael_update,
	.dia_final	= michael_final,
	.dia_setkey	= michael_setkey } }
};


static int __init michael_mic_init(void)
{
	return crypto_register_alg(&michael_mic_alg);
}


static void __exit michael_mic_exit(void)
{
	crypto_unregister_alg(&michael_mic_alg);
}


module_init(michael_mic_init);
module_exit(michael_mic_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Michael MIC");
MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Cryptographic API
	3	*
	4	* Michael MIC (IEEE 802.11i/TKIP) keyed digest
	5	*
85d32e7b	6	* Copyright (c) 2004 Jouni Malinen <j@w1.fi>
1da177e4 LT	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
06ace7a9	13	#include <asm/byteorder.h>
1da177e4 LT	14	#include <linux/init.h>
	15	#include <linux/module.h>
	16	#include <linux/string.h>
	17	#include <linux/crypto.h>
06ace7a9	18	#include <linux/types.h>
1da177e4 LT	19
	20
	21	struct michael_mic_ctx {
	22	u8 pending[4];
	23	size_t pending_len;
	24
	25	u32 l, r;
	26	};
	27
	28
	29	static inline u32 xswap(u32 val)
	30	{
	31	return ((val & 0x00ff00ff) << 8) \| ((val & 0xff00ff00) >> 8);
	32	}
	33
	34
	35	#define michael_block(l, r) \
	36	do { \
	37	r ^= rol32(l, 17); \
	38	l += r; \
	39	r ^= xswap(l); \
	40	l += r; \
	41	r ^= rol32(l, 3); \
	42	l += r; \
	43	r ^= ror32(l, 2); \
	44	l += r; \
	45	} while (0)
	46
	47
6c2bb98b	48	static void michael_init(struct crypto_tfm *tfm)
1da177e4	49	{
6c2bb98b	50	struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
1da177e4 LT	51	mctx->pending_len = 0;
	52	}
	53
	54
6c2bb98b HX	55	static void michael_update(struct crypto_tfm tfm, const u8 data,
6c2bb98b HX	56	unsigned int len)
1da177e4	57	{
6c2bb98b	58	struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
06ace7a9	59	const __le32 *src;
1da177e4 LT	60
	61	if (mctx->pending_len) {
	62	int flen = 4 - mctx->pending_len;
	63	if (flen > len)
	64	flen = len;
	65	memcpy(&mctx->pending[mctx->pending_len], data, flen);
	66	mctx->pending_len += flen;
	67	data += flen;
	68	len -= flen;
	69
	70	if (mctx->pending_len < 4)
	71	return;
	72
06ace7a9 HX	73	src = (const __le32 *)mctx->pending;
06ace7a9 HX	74	mctx->l ^= le32_to_cpup(src);
1da177e4 LT	75	michael_block(mctx->l, mctx->r);
	76	mctx->pending_len = 0;
	77	}
	78
06ace7a9 HX	79	src = (const __le32 *)data;
06ace7a9 HX	80
1da177e4	81	while (len >= 4) {
06ace7a9	82	mctx->l ^= le32_to_cpup(src++);
1da177e4	83	michael_block(mctx->l, mctx->r);
1da177e4 LT	84	len -= 4;
	85	}
	86
	87	if (len > 0) {
	88	mctx->pending_len = len;
06ace7a9	89	memcpy(mctx->pending, src, len);
1da177e4 LT	90	}
	91	}
	92
	93
6c2bb98b	94	static void michael_final(struct crypto_tfm tfm, u8 out)
1da177e4	95	{
6c2bb98b	96	struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
1da177e4	97	u8 *data = mctx->pending;
06ace7a9	98	__le32 dst = (__le32 )out;
1da177e4 LT	99
	100	/* Last block and padding (0x5a, 4..7 x 0) */
	101	switch (mctx->pending_len) {
	102	case 0:
	103	mctx->l ^= 0x5a;
	104	break;
	105	case 1:
	106	mctx->l ^= data[0] \| 0x5a00;
	107	break;
	108	case 2:
	109	mctx->l ^= data[0] \| (data[1] << 8) \| 0x5a0000;
	110	break;
	111	case 3:
	112	mctx->l ^= data[0] \| (data[1] << 8) \| (data[2] << 16) \|
	113	0x5a000000;
	114	break;
	115	}
	116	michael_block(mctx->l, mctx->r);
	117	/* l ^= 0; */
	118	michael_block(mctx->l, mctx->r);
	119
06ace7a9 HX	120	dst[0] = cpu_to_le32(mctx->l);
06ace7a9 HX	121	dst[1] = cpu_to_le32(mctx->r);
1da177e4 LT	122	}
	123
	124
6c2bb98b	125	static int michael_setkey(struct crypto_tfm tfm, const u8 key,
560c06ae	126	unsigned int keylen)
1da177e4	127	{
6c2bb98b	128	struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
06ace7a9 HX	129	const __le32 data = (const __le32 )key;
06ace7a9 HX	130
1da177e4	131	if (keylen != 8) {
560c06ae	132	tfm->crt_flags \|= CRYPTO_TFM_RES_BAD_KEY_LEN;
1da177e4 LT	133	return -EINVAL;
1da177e4 LT	134	}
06ace7a9 HX	135
	136	mctx->l = le32_to_cpu(data[0]);
	137	mctx->r = le32_to_cpu(data[1]);
1da177e4 LT	138	return 0;
	139	}
	140
	141
	142	static struct crypto_alg michael_mic_alg = {
	143	.cra_name = "michael_mic",
	144	.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
	145	.cra_blocksize = 8,
	146	.cra_ctxsize = sizeof(struct michael_mic_ctx),
	147	.cra_module = THIS_MODULE,
e1147d8f	148	.cra_alignmask = 3,
1da177e4 LT	149	.cra_list = LIST_HEAD_INIT(michael_mic_alg.cra_list),
	150	.cra_u = { .digest = {
	151	.dia_digestsize = 8,
	152	.dia_init = michael_init,
	153	.dia_update = michael_update,
	154	.dia_final = michael_final,
	155	.dia_setkey = michael_setkey } }
	156	};
	157
	158
	159	static int __init michael_mic_init(void)
	160	{
	161	return crypto_register_alg(&michael_mic_alg);
	162	}
	163
	164
	165	static void __exit michael_mic_exit(void)
	166	{
	167	crypto_unregister_alg(&michael_mic_alg);
	168	}
	169
	170
	171	module_init(michael_mic_init);
	172	module_exit(michael_mic_exit);
	173
	174	MODULE_LICENSE("GPL v2");
	175	MODULE_DESCRIPTION("Michael MIC");
85d32e7b	176	MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");